Deck 7: River Meandering, Training and Hydroelectricity

Question 1

The main cause of meandering is

A)presence of an excessive bed slope in the river
B)degradation
C)the extra turbulence generated by the excess of river sediment during floods
D)none of the above

Answer 1

the extra turbulence generated by the excess of river sediment during floods

Question 2

Tortuosity of a meandering river is always

A)equal to 1
B)less than 1
C)greater than 1
D)less than or equal to 1

Answer 2

greater than 1

Question 3

Select the correct statement.

A)A meander increases the river length but a cut off reduces the river length.
B)A cutoff increases the river length but a meander reduces the river length.
C)Both meander and cutoff increase the river length.
D)Both meander and cutoff decrease the river length.

Answer 3

A meander increases the river length but a cut off reduces the river length.

Question 4

River training for depth is achieved by

A)groynes
B)construction of dykes or leavees
C)both (a) and (b)
D)groynes and bandalling

Question 5

Main purpose of mean water training for rivers is

A)flood control
B)to provide sufficient depth of water in navigable channels, during low water periods
C)to preserve the channel in good shape by efficient disposal of suspended and bed load
D)all of the above

Question 6

If D is the depth of scour below original bed, then the width of launching apron is generally taken as

A)1.2 D
B)1.5 D
C)2.0 D
D)2.5 D

Question 7

Study the following statements.
i. Levees are constructed parallel to river flow
ii. Spurs are constructed parallel to river flow
iii. Levees are constructed transverse to river flow
iv. Spurs are constructed transverse to river flow.
The correct answer is

A)(i) and (ii)
B)(i) and (iv)
C)(ii) and (iii)
D)(iii) and (iv)

Question 8

A repelling groyne is aligned

A)pointing upstream
B)pointing downstream
C)perpendicular to bank
D)parallel to bank

Question 9

A river training work is generally required when the river is

A)aggrading type
B)degrading type
C)meandering type
D)both (a) and (b)

Question 10

A river bend characterized by silting

A)scouring on concave side
B)silting on convex side
C)scouring on convex side and on concave side
D)scouring on concave side and silting on convex side

Question 11

Select the incorrect statement.

A)Intensive irrigation should be avoided in areas susceptible to water logging.
B)Extensive irrigation should be adopted in areas susceptible to water logging.
C)Lift irrigation increases water logging.
D)all of the above

Question 12

A land is known as waterlogged

A)when the permanent wilting point is reached
B)when gravity drainage has ceased
C)capillary fringe reaches the root zone of plants
D)none of the above

Question 13

Lining of irrigation channels

A)increases the waterlogging area
B)decreases the waterlogging area
C)does not change the water logging area
D)none of the above

Question 14

A runoff river plant is

A)a low head scheme
B)a medium head scheme
C)a high head scheme
D)none of the above

Question 15

The net speed under which the turbine reaches its peak efficiency is called

A)design speed
B)rated speed
C)gross speed
D)operating speed

Question 16

A runoff river plant

A)is a medium head scheme
B)generates power during peak hours only
C)is suitable only on a perennial river
D)has no pondage at all

Question 17

The net head under which the turbine reaches its peak efficiency at synchronous speed is called

A)design head
B)rated head
C)gross head
D)operating head

Question 18

The ratio of the average load to the installed capacity of the plant whose reserve capacity is zero will be equal to

A)load factor
B)plant factor
C)utilisation factor
D)both (a) and (b)

Question 19

A hydroelectric scheme operating under a head of 80 m will be classified as

A)low head scheme
B)medium head scheme
C)high head scheme
D)none of the above

Question 20

A hyetograph is a graphical representation of

A)rainfall intensity and time
B)rainfall depth and time
C)discharge and time
D)cumulative rainfall and time

Question 21

Variability of rainfall is
i. largest in regions of high rainfall
ii. largest in coastal areas
iii. largest in regions of scanty rainfall
The correct answer is

A)only (i)
B)(i) and (ii)
C)only (iii)
D)(ii) and (iii)

Question 22

In India, which of the following is adopted as standard recording raingauge ?

A)Symon's raingauge
B)tipping bucket type
C)natural syphon type
D)weighing bucket type

Question 23

The maximum average depth due to one day storm over an area of 100 km² is 100 mm. Depth-Area-Duration (DAD) curves indicate that for the same area of 100 km² the maximum average depth for a 3 hour storm will be

A)100 mm
B)more than 100 mm
C)less than 100 mm
D)none of the above

Question 24

The maximum rainfall depth of 300 mm in 24 hours has a return period of 100 years. The probability of 24 hours rainfall equal to or greater than 300 mm occurring at least once in 10 years is given by

A)(0.99)¹⁰
B)1 - (0.99)¹⁰
C)(0.9)¹⁰⁰
D)l-(0.9)¹⁰⁰

Question 25

The most suitable chemical which can be applied to the water surface for reducing evaporation is

A)methyl alcohol
B)ethyl alcohol
C)cetyl alcohol
D)butyl alcohol