Deck 6: Hydraulic Structures and Channels

Question 1

As compared to crest of the normal portion of the weir, the crest of the under sluice portion of weir is kept at

A)lower level
B)higher level
C)same level
D)any of the above depending on the design

Answer 1

lower level

Question 2

Silt excluders are constructed on the

A)river bed upstream of head regulator
B)river bed downstream of head regulator
C)canal bed upstream of head regulator
D)canal bed downstream of head regulator

Answer 2

river bed upstream of head regulator

Question 3

According to Khosla's theory, the exit gradient in the absence of a downstream cutoff is

A)0
B)unity
C)infinity
D)very large

Answer 3

infinity

Question 4

The minimum size of stone that will remain at rest in a channel of longitudinal slope S and hydraulic mean depth R is given by

A)4RS
B)11 RS
C)7RS
D)15 RS

Question 5

The ratio of average values of shear stresses produced on the bed and the banks of a channel due to flowing water is

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

Question 6

If the critical shear stress of a channel is xc, then the average value of shear stress required to move the grain on the bank is

A)0.5 xc
B)0.75 TC
C)xc
D)1.33 TC

Question 7

As per Lacey's theory, the silt factor is

A)directly proportional to average par¬ticle size
B)inversely proportional to average par¬ticle size
C)directly proportional to square root of average particle size
D)not related to average particle size

Question 8

Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey's theory will be

A)19 m
B)38m
C)57m
D)76m

Question 9

Which of the following canal structures is used to remove surplus water from an irrigation channel into a natural drain ?

A)canal fall
B)canal outlet
C)canal escape
D)canal regulator

Question 10

For a proportional outlet, the flexibility is

A)zero
B)between zero and 1
C)1
D)greater than 1

Question 11

The sensitivity of a rigid module is

A)zero
B)between zero and one
C)1
D)infinity

Question 12

Which of the following is a flexible outlet ?

A)submerged pipe outlet
B)Kennedy's gauge outlet
C)Gibb's outlet
D)none of the above

Question 13

A straight glacis type fall with a baffle platform and a baffle wall is called

A)vertical dropfall
B)glacis fall
C)Montague type fall
D)inglis fall

Question 14

Which of the following types of falls use parabolic glacis for energy dissipation ?

A)vertical drop fall
B)glacis fall
C)Montague type fall
D)inglis fall

Question 15

In a Sarda type fall, rectangular crest is used for discharge upto

A)6 cumecs
B)10 cumecs
C)14 cumecs
D)20 cumecs

Question 16

Which of the following can be used as a meter fall ?

A)vertical drop fall
B)flumed glacis fall
C)unflumed glacis fall
D)all of the above

Question 17

Vertical drop fall is satisfactory for a height upto

A)0.5 m
B)1.5 m
C)3.5 m
D)5.0 m

Question 18

Which of the following canal outlets maintains a constant discharge ?

A)non-modular outlet
B)flexible outlet
C)rigid module
D)none of the above

Question 19

The ratio of rate of change of the discharge of an outlet to the rate of change of the discharge of distributing channel is called

A)proportionality
B)flexibility
C)setting
D)sensitivity

Question 20

The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in

A)aqueduct and syphon aqueduct
B)aqueduct and super passage
C)super passage and canal syphon
D)level crossing

Question 21

If the R.L's of canal bed level and high flood level of drainage are 212.0 m and 210.0 m respectively, then cross drainage work will be

A)aqueduct
B)superpassage
C)syphon
D)syphon aqueduct

Question 22

The aqueduct or superpassage type of works are generally used when

A)high flood drainage discharge is small
B)high flood drainage discharge is large and short lived
C)high flood drainage discharge is large and continues for a long time
D)none of the above

Question 23

An aggrading river is a

A)silting river
B)scouring river
C)both silting and scouring river
D)neither silting nor scouring river

Question 24

Tortuosity of a meandering river is the ratio of

A)meander belt to meander length
B)meander length to meander belt
C)curved length along the channel to the direct axial length of the river reach
D)direct axial length of the river reach to curved length along the channel

Question 25

The meander pattern of a river is developed by

A)average discharge
B)dominant discharge
C)maximum discharge
D)critical discharge